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Oct. 5, 2011 -- New research raises concerns about a rise in potentially serious infections that require hospitalization in men who have prostate biopsies.

Men in the study who had the biopsies were more than twice as likely as those who didn't to be hospitalized within the next 30 days for infections, bleeding, or other causes, researchers with Johns Hopkins University School of Medicine reported.

Researchers compared the medical records of close to 17,500 men who had prostate biopsies to about 135,000 men with similar characteristics who did not have them.

Within a month of having the procedure, 6.9% of men who had prostate biopsies were hospitalized, compared to 2.9% of non-biopsied men followed over the same time period.

Prostate biopsies are most often performed to confirm or rule out prostate cancer.

Researcher Stacy Loeb, MD, who is now an instructor in urology at New York University, says the findings appear to confirm reports of an increase in antibiotic-resistant infections associated with prostate biopsy.

But she adds that the findings should not deter men who need them from having the procedures.

"We can't treat men for prostate cancer until we know they have it, and we really don't have any other way of knowing for sure that this is the case without doing a biopsy," she says.

Prostate Biopsies and Antibiotic Resistance

The analysis is one of the largest ever performed to assess complications associated with prostate biopsies in men who were 65 and older.

Researchers analyzed Medicare records of hospitalizations between 1991 and 2007, finding a steady rise in the rate of serious infection-related complications among men who underwent prostate biopsies.

More than 1 million prostate biopsies are performed each year in older men who are eligible for Medicare.

In 1991, fewer than 0.5% of men in the study who had biopsies were admitted to the hospital for infections following the procedures, but this complication had increased to more than 1.2% of men by 2007.

This increase may be largely explained by a rise during the same time period in resistance to fluoroquinolone antibiotics, which are routinely given prior to prostate biopsies to prevent infections related to the procedure, the researchers suggest.

The researchers estimate that one additional hospitalization for infection, bleeding, or aggravation of existing health conditions could be expected for every 24 men undergoing biopsies.

Recent Hospitalization Raises Risk

Loeb says the recognition that increasing fluoroquinolone resistance is a significant contributor to prostate biopsy complications can help urologists combat the problem.

While it would be impractical to test every patient for antibiotic resistance, she says asking patients a few simple questions can help identify those at risk.

"Red flags for potential resistance are a recent hospitalization and recent use of antibiotics," she tells WebMD. "If we know a patient has either of these risk factors, we can give different antibiotics prior to biopsy."

New York University urologist Herbert Lepor, MD, who was not involved with the study, says the findings appear to confirm what he is seeing in the clinic.

"We have performed thousands of biopsies over the last few years, and we are definitely seeing more resistance," he tells WebMD. "The risk to the individual patient remains quite low, but in an older patient it can be fatal."

Lepor says he now gives more powerful, broad-spectrum antibiotics to patients with risk factors for resistance to fluoroquinolones.

SOURCES:Loeb, S. The Journal of Urology, November 2011.Stacy Loeb, MD, instructor in urology, NYU Langone Medical Center, New York City.Herbert Lepor, MD, professor and chairman, department of urology, NYU School of Medicine, New York City.News release, Johns Hopkins Medicine.